The present invention relates to a car order selecting system for a railway train in which data series-connected transmitting devices are provided on the various cars.
Heretofore, the arrangement of railway cars having series-connected data transmitting devices has been fixed. A data transmitting device serving as the central station is installed on the front car and data transmitting devices serving as terminal station are installed on the following cars. Accordingly, the positional order of the data transmitting devices on the cars is physically fixedly determined, and therefore the data transmitting device serving as the central station carries out transmission control according to station numbers and the positional order of the data transmitting devices, which have been registered in advance in accordance with a polling selection transmission procedure.
FIG. 1 is a connection diagram of a railway car order selecting device of a type described, for instance, in "Collection of Railway Cybernetics Utilization Domestic Symposium Papers", vol. 19, pp. 496. As shown in FIG. 1, data transmitting devices 104a, 104b and 104c, corresponding to the first, second and third railway cars, are provided on railway cars 101, 102 and 103, respectively. These devices 104a, 104b and 104c are connected through transmitting lines 105. The train is fixedly formed by three cars, the first through third carriages.
The operation of the car order selecting device will be described. The data transmitting device on one (the front carriage 101 or 103) of the three cars 101 through 103 operate as the central station, and the remaining data transmitting devices serve as terminal stations. It is assumed that the first car 101 is the front car. In this case, the data transmitting device 104a is the central station. The central station 104a polls the terminal stations 104b and 104c successively to collect data from the terminal stations. The data thus collected is edited and displayed on a display unit 106a. The data thus displayed is transmitted to the terminal station through the transmitting lines 105 so as to be displayed on the display unit 106c. The terminal stations 104b and 104c have car number selecting switches (not shown) to determine their own station numbers (such as 2 and 3). Each terminal station transmits (automatic data) to the central station 104a only when requested to answer with its station number specified. However, since the cars are in the fixed formation, they must be arranged in the order of numbers.
As is apparent from the above description, the conventional car order selecting system is of the semifixed type in which the station numbers of the data transmitting devices are determined by operating selecting switches corresponding to the car numbers. Therefore, when trains are combined together, a plurality of data transmitting devices have the same station number, as a result of which it becomes difficult to transmit data between the data transmitting devices, and it is impossible to accurately detect the positions of the various cars in the train.
In a variable formation type train of more than two cars in which the front-to-rear direction of a car can be changed whenever it is connected, the central station on the front car cannot detect the numbers of terminal stations provided on the following cars or the station numbers and the positional order of the terminal stations. Therefore, the central station cannot communicate with the terminal stations, and cannot display data such as the name of equipment which is out of order and the position of the car having the equipment. Furthermore, in the case where it is required to provide some indication to the operator in response to the data of the data transmitting devices, even if it were possible to communicate with the data transmitting device, it would be impossible to communicate to the operator the correct data because the positional order of the data transmitting device is unknown.